Revealing mistakes: In episode #5, "Masques", there is a shot where Vincent has no make-up on his hand.
Continuity: In "Seige", Catherine visits Vincent in the tunnels and he is heartbroken that she is falling in love with good looking businessman Elliot Burch. Vincent turns to go back into the tunnel and Catherine sadly watches him go. As he turns back to look at her, the hood on his cloak is down. The camera turns to Catherine, then back to Vincent who's hood is now on, then back to Catherine and once again, back to Vincent who's hood is once again off, as he turns to go inside.
Continuity: In the first part of “Though Lovers Be Lost”, Catherine stands on her balcony, waiting for Vincent to come. She is wearing a green coat. When she realizes Vincent isn't coming, she heads for the tunnels. But when she arrives there, she is wearing a totally different coat, and her hair is falling different as well.